There is this option. http://www.rutlands.co.uk/sp+woodworking-power-tool-accessories-router-tables-router-lifts-inserts-precision-router-lift-and-variable-speed-motor-combo-kit-rutlands+rtx5000combo
Lifter and spindle together.
The biggest issue we have with our router table is all lifters use a square insert that slots into the table which is not possible with ours as our back part of the table is cast iron. But I am sure we could make one.
Going this route would allow us to use the current router on the table as a dedicated circle cutter. Which I know @joeatkin2 thinks is a good idea